Verification of Authenticity

• US 20070028093A1
• Filed: 07/27/2006
• Published: 02/01/2007
• Est. Priority Date: 07/27/2005
• Status: Active Grant

• Current Assignee: Ingenia Holdings Limited
• Original Assignee: Ingenia Holdings Limited
• Inventors: Buchanan, James, Cowburn, Russell
• Granted Patent: US 8,078,875 B2
• Time in Patent Office: Days
• US Class Current: 713/155
• CPC Class Codes: G06Q 10/02 Reservations, e.g. for tickets, services or events
• CPC Class Codes: G06V 10/28 Quantising the image, e.g. histogram thresholding for discrimination between background and foreground patterns
• CPC Class Codes: G06V 10/40 Extraction of image or video features
• CPC Class Codes: G06V 10/42 Global feature extraction by analysis of the whole pattern, e.g. using frequency domain transformations or autocorrelation
• CPC Class Codes: G06V 20/80 Recognising image objects characterised by unique random patterns
• CPC Class Codes: G07D 7/003 using security elements using digital security elements G07D7/004

Abstract

An article identification method can comprise: determining a signature from an article based upon an intrinsic characteristic of the article; and comparing the determined signature to a stored signature. The method can also comprise splitting the determined signature into blocks of contiguous data, performing a comparison operation between each block and respective blocks of the stored signature, and comparing an attribute of a comparison result from each block comparison to an expected attribute of the block comparison to determine a compensation value for use in determining a comparison result. The method can also comprise determining a similarity result between the determined signature and the stored signature, using the compensation value to adjust the determined signature. Thus an article damaged by stretching or shrinking can be successfully identified. Also, a non-linear signature determination can be accommodated without losing identification accuracy.

Claims

1. A system for identifying an article, the system comprising:

a signature determination unit operable to determine a signature from an article, the signature determination unit comprising;

a reading volume for receiving an article;

a source for generating a coherent beam and directing the coherent beam sequentially onto a plurality of regions of a surface of an article in the reading volume;

a detector arrangement for collecting a set comprising groups of data points from signals obtained when the coherent beam scatters from the different regions of an article in the reading volume, wherein different ones of the groups of data points relate to scatter from respective different regions of the article; and

a data acquisition and processing unit for determining a signature of the article from the set of groups of data points; and

a comparison unit operable to compare the determined signature to a stored signature;

wherein the comparison unit is operable to split the determined signature into blocks of contiguous data and to perform a comparison operation between each block and respective blocks of the stored signature.

2. The system of claim 1, wherein the comparison unit is further operable to compare an attribute of a comparison result from each block comparison to an expected attribute of block the comparison to determine a compensation value for use in determining a comparison result;

and wherein the comparison unit is further operable to determine a similarity result between the determined signature and the stored signature, using the compensation value to adjust the determined signature.

3. The system of claim 2, wherein the comparison unit is operable to apply the compensation value to adjust the determined signature to compensate for damage to the access token and/or a non-linearity in the determination of the determined signature.

4. The system of claim 3, wherein the comparison unit is operable to apply the compensation value to adjust the determined signature to compensate for a non-linearity in the relationship between the different parts of the reading volume.

5. The system of claim 1, wherein the reading volume is arranged such that the article can be moved relative to the detector arrangement.

6. The system of claim 1, wherein the detector arrangement is operable to be moved relative to the reading volume.

7. The system of claim 2, wherein the comparison unit is operable to compare an actual cross-correlation peak location of a comparison result between a block of the determined signature and the corresponding block of the stored signature to an expected cross correlation peak location to determine the compensation value for use in determining a comparison result.

8. The system of claim 7, wherein the comparison unit is operable to determine the compensation value by estimating a function of best fit to the cross-correlation peak locations for each of the block comparisons, the function of best fit representing an average deviation from the expected cross-correlation peak locations.

9. The system of claim 8, wherein the function of best fit is one of a straight line function, an exponential function, a trigonometric function and an x² function.

10. The system of claim 1, operable to compare the determined signature to a plurality of stored signatures.

11. The system of claim 10, operable to find a closest match result between the determined signature and the plurality of stored signatures.

12. The system of claim 9, operable to return a no match result if the determined signature has determined therefor a similarity result lower than a predetermined threshold for each of the stored signatures.

13. The system of claim 1, wherein the comparison unit is operable to calculate a similarity result for each compared block.

14. The system of claim 13, wherein the comparison unit is operable to compare the similarity result for at least one predetermined block to a predetermined similarity threshold.

15. The system of claim 14, wherein a comparison unit is operable to return a negative comparison result in the event of the similarity result for the at least one predetermined block being below a predetermined similarity threshold, regardless of a similarity result for the signatures as a whole.

16. An article identification method, comprising:

determining a signature from an article, wherein determining the signature comprises;

directing coherent radiation sequentially onto a plurality of regions of a surface of an article in the reading volume;

collecting a set of data points comprising groups of data points from signals obtained when the coherent radiation scatters from intrinsic structure of the article, wherein different ones of the groups relate to scatter from respective different regions of the article; and

determining a signature of the article from the set of data points;

comparing the determined signature to a stored signature;

splitting the determined signature into blocks of contiguous data; and

performing a comparison operation between each block and respective blocks of the stored signature.

17. The method of claim 16, further comprising:

comparing an attribute of a comparison result from each block comparison to an expected attribute of the block comparison to determine a compensation value for use in determining a comparison result; and

determining a similarity result between the determined signature and the stored signature, using the compensation value to adjust the determined signature.

18. The method of claim 17, further comprising applying the compensation value to adjust the determined signature to compensate for damage to the article and/or a non-linearity in the determination of the determined signature.

19. The method of claim 18, comprising applying the compensation value to adjust the determined signature to compensate for a non-linearity in the relationship between different parts of the article.

20. The method of claim 16, wherein collecting the set of data points comprises moving the article can be moved relative to a detector.

21. The method of claim 16, wherein collecting the set of data points comprises moving a detector arrangement relative to the article.

22. The method of claim 17, wherein said comparing an attribute of a comparison result from each block comparison to an expected attribute of the block comparison comprises comparing an actual cross-correlation peak location of a comparison result between a block of the determined signature and the corresponding block of the stored signature to an expected cross correlation peak location to determine the compensation value for use in determining a comparison result.

23. The method of claim 22, wherein said determining the compensation value comprises estimating a function of best fit to the cross-correlation peak locations for each of the block comparisons, the function of best fit representing an average deviation from the expected cross-correlation peak locations.

24. The method of claim 23, wherein the function of best fit is one of a straight line function, an exponential function, a trigonometric function and an x² function.

25. The method of claim 16, comprising comparing the determined signature to a plurality stored signatures.

26. The method of claim 25, further comprising finding a closest match result between the determined signature and the plurality of stored signatures.

27. The method of claim 25, further comprising returning a no-match result if the determined signature has determined therefor a similarity result lower than a predetermined threshold for each of the stored signatures.

28. The method of claim 16, further comprising calculating a similarity result for each compared block.

29. The method of claim 28, further comprising comparing the similarity result for at least one predetermined block to a predetermined similarity threshold.

30. The method of claim 29, further comprising returning a negative comparison result in the event of the similarity result for the at least one predetermined block being below a predetermined similarity threshold, regardless of a similarity result for the signatures as a whole.